Method for preventing choking of oil wells and the like



Patented Nov. 6, 1934 PATENT OFFICE METHOD FOR PREVENTING CHOKING OF OIL WELLS AND THE LIKE John Thomas King, Pampa, Tex.

No Drawing. Application August 27, 1934, Serial No. 741,723

12 Claims. (Cl. 166-21) This invention relates to a method for preventing choking of oil wells or for relieving choked conditions of oil wells and the like which have already become clogged. It has for its general object to overcome difliculties encountered in the operation of both naturally flowing and mechanically or otherwise pumped wells, due to theaccumulation of congealed paramne or other characteristic base or constituent susbtances of the oil, which tend to cause stoppage of the flow and to interfere with the operation of movable pumping and other mechanical elements in the well.

In nearly all producing wells, either naturally flowing or pumped, as just above stated, certain characteristic base or constituent substances of the crude oil, particularly paraifine, and often asphaltum therewith, gradually adhere to and accumulate upon the tubular metal lining or casing of the well and to the pump tubing and movable mechanical elements of the pump, as well as other parts or devices within the well, to such an extent as to appreciably hinder the working of the pump mechanism and to seriously choke the casing and pump tubing.

In some cases complete stoppage occurs, necessitating forced withdrawal of the pump and other parts, and the removal of the accumulation from the tubing by mechanical means, the processpf which entails much labor and expense and loss of time, to say nothing of the loss of output in the meantime. In some cases, too, the choking of the well results in complete abandonment. The application of steam, and even specially provided electrical heating means, has also been resorted to for softening and loosening the congealed, or frozen as it is commonly termed, parafline or other base or constituent substance causing the stoppage. This treatment is not completely satisfactory, especially because the steam is not a solvent for the accumulated substance, and, further, because steam causes injurious effects upon the metal parts within the well. So, too, in other instances, a caustic soda solution or strong acid mixtures have been used, but, obviously, with seriously detrimental effect upon the metal parts due to the treating. material eating into and corroding the metal.

Under practically all conditions and due to the natural base character of the oil produced in the well, there is a steady building up and growth of the heavy base substance of the crude oil, particularly parafline, as hereinbefore mentioned, upon the surfaces of the well lining, pump tubing and other metal parts within the well, usually starting near the top of the well and developing downwardly, although, of course, the accumulation may occur at different lower levels, and, in some cases, near the bottom of the well and at considerable depth.

The congealing and accumulation of the parailine, and naturally other substances therewith, becomes appreciable sooner or later in nearly all oil wells, and sometimes within a few days after the well is brought in, as it is termed, and productive operation is started. This accumulation of parafilne, or other base substance from the crude oil, is bound to occur gradually by a natural adherence to and growth upon the surfaces of the metal parts, as herein stated, but it is principally caused and hastened by the natural refrigerating effect of thegas accompanying the flowing crude oil in sufiicient proportion in any case, and varying to a greater or lesser degree in different wells, but to an appreciable degree in all wells. That is to say, the gas being lighter than the bulk of the oily liquid and free therefrom, except as by movable contact therewith, has a higher velocity and its action in moving into contact with the body 'of flowing oil is, in effect, similar to that in mechanical refrigerating apparatus or machines, with the result that the parafiine congeals, or freezes, as it is commonly termed in the parlance of the oil fields.

The present invention, therefore, has for one of its prime objects to provide a practical method of treatment for the prevention of such accumulation as well as the removal of that which has already occurred in oil wells and the like, wherein a non-corrosive liquid composition or mixture consisting of a suitable solvent and a rubber-like carrier or holder therefor is employed to dissolve and dislodge the parafiine and other depositable or deposited base or constituent substance of the oil without any deleterious effect upon the metal parts within the well. Other specific objects and advantages to be attained will hereinafter more fully appear.

The invention consists in the novel method as set forth in the following description and afterwards pointed out with particularity in the appended claims.

Generally and broadly stated, the treating material of the present invention comprises a highly volatile hydrocarbon or other suitable solvent liquid or distillate which will dissolve congealed parafiine and other characteristic base substances or constituents of crude oil which tends to adhere to and accumulate upon the parts, as hereinbefore described, and a rubber-like binder or carrier to retard free evaporation of this volatile liquid, carry the mixture through the body of free 011, and hold the volatile liquid in intimate contact with the free particles of or the deposited congealed substance to be dissolved and removed.

More specifically, an ideal, proven product for the purpose, comprises a mixture of rubber and benzol; and, for practical purposes, it has been found that a mixture of commercial gum rubber dissolved in benzol or other suitable solvent, and of a flowable consistency, say about that of ordinary glycerine, will suflice; or, a ready prepared liquid rubber or rubber by-product, without water content, may be utilized and have added thereto sufficient benzol or other suitable solvent, the basic principle being that rubber is an ideal and preferred carrier and holder for the solvent, and benzol is the preferred solvent. However, the invention comprehends, broadly, the use of equivalent ingredients for the solvent mixture or product.

The mixture just above described, is highly gaseous and inflammable, and therefore, in most cases, to minimize the hazard in its use, it is preferably diluted by adding coal oil or kerosene, which may be in considerable quantity and varying in different treating operations and in different temperatures, the said diluent efiectively reducing inflammability of the mixture, while serving as a filler and at the same time enhancing the penetrability of the product rather than detracting from its eflicacy, and also preventing freezing of the mixture, in relatively low temperature.

The method of the present invention broadly resides and consists in the utilization of a noncorrosive liquid of high solvent character, mixed with a similarly non-corrosive binder or carrier,

which, when applied in the well, carries the sol-.

ventthrough the body of oil produced in the well and also holds the solvent in intimate contact with the congealed substance until the latter is dissolved, and, further, in the manner of applying the liquid solvent mixture to the well either during productive operation or after cessation of productive operation, as will be presently more fully described and claimed.

In naturally flowing wells, the flow is not usually continuous, but interruptedly, the flow of the oil occurring for a period followed by a period of rest, alternate flow and cessation taking place with rather definite regularity. During the period of cessation the well hole is free of oil, at least to a considerable depth from the top, and during this time a quantity of the liquid solvent mixture is poured into the well where it, or a portion thereof, lodges in contact with such accumulation of the congealed paraffine or other substances as may be found in the well, and that portion of the applied mixture which does not so lodge passes on until it reaches and mingles in the body of free oil in the well. 7

In some pumped wells, after the shutting down of productive operation, as is usually done each day, or at other intervals, or specially for treatment in accordance with the present invention, in some cases there is no head or column of oil reaching all the way to the top, in which cases, the solvent mixture is readily applied by pouring it without the necessity of employing mechanical means or other agency to force the liquid into the well. However, in other cases, there may be .a head or column of oil all the way to the top of the well. In these instances the treating liquid is forced into the well, by suitable means, through which it is readily and practically accomplished, the liquid being carried downwardly in the space between the well lining tube or casing and the pump tubing or rod. In this connection, also, by connecting up with the pump mechanism the means or devices employed for ap plying the treating liquid, the treatment is carried on during the pumping operation and may be continued for a given time or with continued regularity from time to time, whereby choking of the well is practically prevented.

While the invention is primarily brought about to prevent choking and ultimate stoppage of oil flow and interference with the normal operation' of the pumping mechanism, the treatment in accordance with the method set out herein is also effective in clearing wells already partially clogged by an accumulation of paraifine, with or without other substances attached thereto or embedded therein, and the treatment is even practically effective in opening completely closed wells. In every case, the result is accomplished with relative economy, in minimum time, and without injury to metal parts, because of the highly solvent and non-corrosive character of the treating mixture.

The invention is not limited to the treatment of base or constituent substances of oil as produced in the well, but is applicable with the same effect in the prevention and relief of clogging in pipe connections and containers employed in conveying and handling the oil from the well and at certain stages in its treatment before refinement.

Obviously, as hereinbefore stated, the invention is not limited to the use of the specific preferred and practical ingredients of the liquid solvent mixture,-nor to any fixed proportions thereof, but comprehends modification and substitution of equivalents for the specified preferred ingredients within the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. The method of preventing or relieving accumulation of congealed base or other constituent substances of oil in wells and the like, consisting in applying in the well or container a liquid composition comprising a volatile solvent for the congealed substance and a rubber-like substance as a carrier for the solvent.

2. The method of preventing or relieving accumulation of congealed base or other constituent substances of oil in wells and the like, consisting in applying in the well or container a noncorrosive liquid composition comprising a solvent for the congealed substance and rubber as a carrier for the solvent.

3. The method of preventing or relieving accumulation of congealed parafline or other cohering base or constituent substances of oil in wells and the like, consisting in applying in the well or container a liquid composition comprising benzol as a solvent and rubber as a carrier for the benzol.

4. The method of preventing or relieving accumulation of .soluble substances congealable in oil wells and the like, consisting in applying to the well or container a liquid composition comprising a volatile solvent for the congealable substance of non-corrosive character and a rubberlike substance as a carrier for the solvent, and circulating the composition through the well or container and into contact with the free or lodged congealed substance.

5. The method of treating oil wells for preventing or relieving accumulation of congealed tive operation of the well.

'7. The method as set forth in claim 5, wherein the treatment is eifected by forcible means operating simultaneously with productive operation of the well to forcibly carry the treating compound through the space between the well casing and inner mechanical parts.

8. The treatment of oil wells for the purposes described, which comprises passing a mixture of a non-corrosive volatile solvent and a rubberlike substance as a carrier for said solvent through the body of produced free oil in the well and into intimate contact with the congealable base of the oil.

9. The treatment of oil wells for the purposes described, which comprises passing a mixture of a non-corrosive volatile solvent and a rubberlike material as a carrier for'said solvent through the body of produced free oil and into intimate contact with said oil, with solvent effect upon the free particles of congealed base of the oil and upon the lodged congealed substance.

10. The treatment of an operating, productive oil well for the purposes described, by forcibly circulating through the body of produced free oil, during operation and by mechanical means working simultaneously with the regular well-operating mechanical means, a liquid composition comprising a non-corrosive volatile solvent and a rubber-like material as a carrier or holder agent.

11. The treatment of oil wells by the mechanical means and under the working conditions as set forth in claim 10, wherein the liquid composition comprises a mixture of benzol and rubber.

12. A method of treating oil wells or the like to prevent clogging or to relieve an already existing clogged condition, which consists in applying in the well or container a composition comprising a volatile solvent for the clogging material and a carrier for the solvent having the characteristics of rubber.

JOHN THOMAS KING. 

